In previous years, team participants included Danni's friends and family, netball teammates, women from her Winston Hills mothers' group and women she met through her daughter's preschool, Little Angels at Baulkham Hills.

Mrs Robertson said she continued to participate in the fun run each year in her sister's memory and for all the "inspiring" people battling cancer, as well as to help raise much-needed money for research into treatments and cures.

"Every year, Danni participated despite the treatment she was undergoing or how poor she was feeling," Kate said.

"She was fully aware of the need for research into treatment to fight this disease.

"New treatments helped her survive a bit longer.

"That's why we do it every year, to help."

The 2014 Mother's Day Classic will take place on May 11 at Parramatta Park.